rosette nebula ngc 2237 sho palette Javier Zayas Photography//Getty Images For decades, scientists have discerned that the universe is not only expanding, but accelerating. But this evidence doesn’t always square with models, throws flags with things like the cosmological constant, and makes explanations like dark energy necessary A new paper from a researcher at the University of Geneva goes back to the drawing board and proposes a new idea—that our perception of an expanding universe could be a mirage.